Cloning And Expression Analysis Of Edg Family Receptors During Early Chick Development

Edg(Endothelial differentiation gene) family receptors belong to the G protein-coupled receptors(GPCR) subfamily.Up to now,eight members of this family have been found in human and in mice,and they can be classified into two subfamilies based on their ligand specificity:the S1P receptor subfamily,including S1p1(Edg1),S1p2(Edg5/H218/AGR16),S1p3(Edg3),S1p4(Edg6) and S1p5 (Edg8);and the LPA receptor subfamily,including Lpa1(Edg2/VZG-1),Lpa2(Edg4) and Lpa3(Edg7).These receptors mediate SIP and LPA signals respectively to regulate essential cellular processes,such as cell proliferation,migration, differentiation,cytoskeletal organization,and apoptosis.Some of them have been shown involved in activities including vascular and vervous development, reproduction,transplant immunity,autoimmune diseases,wound healing,asthma and tumorigenesis.Though they are defined as endothelial differentiation genes,only S1p1 was demonstrated to be involved in the regulation of vascular development in mice,the roles of other members in vascular system have not been dissected till now. Moreover,we have very little information about the function of this receptors family in other organisms.To better unstandand the biological funcation of Edg family receptors,we chose chick as study model.Chick is an excellent model for in vovo analysis of gene function,due to its easy resource,convenience of manipulations and observations,short experimental period.The present thesis reports our results on cloning and expression analysis of this receptor family in chick.We found that there are at least six members of this family in chick,they are S1p1,S1p3,S1p4,Lpa1,Lpa2 and Lpa3.We deduced the cDNA sequences,which containing the whole open reading frame,for all these six members by using In Silico Cloning strategy.All these cDNA sequences were subsequently cloned from 5-day-old chick embryo.By applying whole-mount in situ hybridization,we have got the expression patterns of Edg family receptors during chick early development.Our results suggested:during chick development, S1p1,S1p3 and Lpa1 exhibit restricted expression patterns while S1p4,Lpa2 and Lpa4 exhibit a sort of diffused or weak expression;A variety of the chick organ primordia,including cardiovascular system,the developing brain,branchial arches, somites,eye,wing bud,and leg bud,express several members of these receptors; Comparing to the mouse,the expression patterns of these receptors share both identity and diversity in the early developmental embryos.Our study provided venerable information for further funtional studies of the Edg family receptors in chick,and their functon comparison among different organisms.